fix(mypy): type annotations for conversions algorithms

.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
           python -m pip install mypy pytest-cov -r requirements.txt
       # FIXME: #4052 fix mypy errors in the exclude directories and remove them below
       - run: mypy --ignore-missing-imports
-          --exclude '(conversions|data_structures|digital_image_processing|dynamic_programming|graphs|linear_algebra|maths|matrix|other|project_euler|scripts|searches|strings*)/$' .
+          --exclude '(data_structures|digital_image_processing|dynamic_programming|graphs|linear_algebra|maths|matrix|other|project_euler|scripts|searches|strings*)/$' .
       - name: Run tests
         run: pytest --doctest-modules --ignore=project_euler/ --ignore=scripts/ --cov-report=term-missing:skip-covered --cov=. .
       - if: ${{ success() }}

conversions/binary_to_octal.py

@@ -28,7 +28,7 @@ def bin_to_octal(bin_string: str) -> str:
         bin_string = "0" + bin_string
     bin_string_in_3_list = [
         bin_string[index : index + 3]
-        for index, value in enumerate(bin_string)
+        for index in range(len(bin_string))
         if index % 3 == 0
     ]
     for bin_group in bin_string_in_3_list:

conversions/decimal_to_binary.py

@@ -28,9 +28,9 @@ def decimal_to_binary(num: int) -> str:
     TypeError: 'str' object cannot be interpreted as an integer
     """
 
-    if type(num) == float:
+    if isinstance(num, float):
         raise TypeError("'float' object cannot be interpreted as an integer")
-    if type(num) == str:
+    if isinstance(num, str):
         raise TypeError("'str' object cannot be interpreted as an integer")
 
     if num == 0:
@@ -42,7 +42,7 @@ def decimal_to_binary(num: int) -> str:
         negative = True
         num = -num
 
-    binary = []
+    binary: list[int] = []
     while num > 0:
         binary.insert(0, num % 2)
         num >>= 1

conversions/decimal_to_hexadecimal.py

@@ -21,7 +21,7 @@
 }
 
 
-def decimal_to_hexadecimal(decimal):
+def decimal_to_hexadecimal(decimal: float) -> str:
     """
     take integer decimal value, return hexadecimal representation as str beginning
     with 0x
@@ -58,6 +58,7 @@ def decimal_to_hexadecimal(decimal):
     True
     """
     assert type(decimal) in (int, float) and decimal == int(decimal)
+    decimal = int(decimal)
     hexadecimal = ""
     negative = False
     if decimal < 0:

conversions/decimal_to_octal.py

@@ -17,14 +17,14 @@ def decimal_to_octal(num: int) -> str:
     counter = 0
     while num > 0:
         remainder = num % 8
-        octal = octal + (remainder * math.pow(10, counter))
+        octal = octal + (remainder * math.floor(math.pow(10, counter)))
         counter += 1
         num = math.floor(num / 8)  # basically /= 8 without remainder if any
         # This formatting removes trailing '.0' from `octal`.
     return f"0o{int(octal)}"
 
 
-def main():
+def main() -> None:
     """Print octal equivalents of decimal numbers."""
     print("\n2 in octal is:")
     print(decimal_to_octal(2))  # = 2

conversions/prefix_conversions.py

@@ -59,10 +59,12 @@ def convert_si_prefix(
     1000
     """
     if isinstance(known_prefix, str):
-        known_prefix: SI_Unit = SI_Unit[known_prefix.lower()]
+        known_prefix = SI_Unit[known_prefix.lower()]
     if isinstance(unknown_prefix, str):
-        unknown_prefix: SI_Unit = SI_Unit[unknown_prefix.lower()]
-    unknown_amount = known_amount * (10 ** (known_prefix.value - unknown_prefix.value))
+        unknown_prefix = SI_Unit[unknown_prefix.lower()]
+    unknown_amount: float = known_amount * (
+        10 ** (known_prefix.value - unknown_prefix.value)
+    )
     return unknown_amount
 
 
@@ -85,10 +87,10 @@ def convert_binary_prefix(
     1024
     """
     if isinstance(known_prefix, str):
-        known_prefix: Binary_Unit = Binary_Unit[known_prefix.lower()]
+        known_prefix = Binary_Unit[known_prefix.lower()]
     if isinstance(unknown_prefix, str):
-        unknown_prefix: Binary_Unit = Binary_Unit[unknown_prefix.lower()]
-    unknown_amount = known_amount * (
+        unknown_prefix = Binary_Unit[unknown_prefix.lower()]
+    unknown_amount: float = known_amount * (
         2 ** ((known_prefix.value - unknown_prefix.value) * 10)
     )
     return unknown_amount

conversions/weight_conversion.py

@@ -29,7 +29,7 @@
 -> Wikipedia reference: https://en.wikipedia.org/wiki/Dalton_(unit)
 """
 
-KILOGRAM_CHART = {
+KILOGRAM_CHART: dict[str, float] = {
     "kilogram": 1,
     "gram": pow(10, 3),
     "milligram": pow(10, 6),
@@ -42,7 +42,7 @@
     "atomic-mass-unit": 6.022136652e26,
 }
 
-WEIGHT_TYPE_CHART = {
+WEIGHT_TYPE_CHART: dict[str, float] = {
     "kilogram": 1,
     "gram": pow(10, -3),
     "milligram": pow(10, -6),